Mechanism for supplying pulverized fuel to furnaces



Dec. 21,1937.

E. V. FRANCIS MECHANISM FOR SUPPLYING PULVERI ZED FUEL TO FURNACES Original Filed Jan. 18,1933

2 Sheets-Sheet 1 [N VEN TO Ear/e V Fran c/s,

BY O -A 777.M4,

ATT'X 1937. E. v. FRANCIS 2,102,948

MECHANISM FOR SUPPLYING PULVERIZED FUEL TO FURNACES Original Filed Jan. 18, 1953 2 Sheets-Sheet 2 Ear/e Vf'ranc/ 's,

A TT'Y Patented n... 21, 1937 UNITED STATES PATENT OFFICE MECHANISM FOR SUPPLYING rULvEmzEn FUEL r FURNACES Earle V. Francis, Columbus, Ohio, assignor to The Jeffrey Manufacturing Company, a corporation of Ohio Original application January 18, 1933, Serial No. 652,347. Divided and this application May 24,

1934, Serial No. 727.270

12 Claims. (Cl. 221-125) nism for feeding from storage pulverulent matefeeding and mixing mechanism employed for feeding powdered coal into a suitable burner therefor;

Fig. 2 is an elevational view, partly in section, of that portion of Fig, 1 to the left of the fan shaft therein; I

Fig. 3 is a, plan view of the feeding and mixing mechanism shown in Figs. 1 and 2, but with the storage bin removed; and a Fig. 4 is a diagrammatic illustration of a wiring system employed in connection with the present mechanism.

It will beunderstood that the apparatus herein illustrated and described is adapted, among other uses,- for use in connection with an apzitomatic heating system'employing pulverized coal as the fuel such as is described in the parent case, Ser. No. 652,347fabove referred to.

In such adaptation, the powdered fuel, such as pulverized coal, is adapted to be stored in a large bin or casing, the lower end of which is fragmentarily shown at 29, and which is coni- Cal 'or hopper-shaped. This casing is adapted to receive the pulverized coal through a filling 40 opening at'its upper end. To the lower end -of the hopper-shaped portion 29 of the pulverized coal bin is secured a housing 32 formed by a, casting 2 which is providedv with a vertical flange having an annular groove 33 to receive a 4 felt'packlng 34 shown in'Fig. 1, the latter serv-' ing to prevent leakage of pulverized coal from ew 144, as shownin Fig. 3. when the motor;

44 is. operated to rotate the shaft 43 in the take a mixture of pulverized coal and air through the intake opening 45 of thefan casing 46 and blow such mixture through the'pipe 26 into the pipe 25 and thence into the combustion chamber of a furnace (not shown), where the powdered coal is burned.

Thrust bearings for the shaft 40 are provided by securing collars I63, I63 to the shaft 40 as shown in Fig. 1. Lubricating openings may be provided for the journal bearings 41, 48.

Secured rigidly to the top of the worm gear housing 31in stationary position is a circular support or ring housing 49 which is provided with an inner annular groove 50 for receiving a felt packing 5|. The inner lower portion of the ring 49 carries a spider frame 52 comprising a plurality of upwardly and inwardlyinclined arms secured at their upper inner ends to the vertical thrust bearing support 53.

A vertical shaft 54 concentric with the ring 49 is provided with stepped thrust roller bearings at its lower and intermediate portions as shown in Fig. 1. The lower thrust bearing 55 resists movement of the shaft '54 upwardly and outer periphery. or the feed plate is the trailing thereof.

Connected to the outer periphery of the feed plate '51 to occupy a plane'spaoed below the upper horizontal surface of the feed plate 5 111s proper direction, the fan 21 will be operated to an annular plate or flange 59 to serve as an an-.

nular carrier or conveyor as-hereinafter more fully described. The" upper peripheral edge of the annularplate 59 is mounted to engage the bottom of the felt packing 34 so as to effectually confinethe pulverized fuel to the annular passageway 69 which is between the horizontal planes extending through the upper surfaces of the feed plate 51 and the annularcarrier or con- -veyor 59. The passageway 69 affords a peripheral annular enclosure or chamber below the horizontal plane extending through the upper surface of the feed plate 51.

Integral with the annular carrier or conveyor 69 is a depending annular flange 6I, the outer surface of which is adapted to engage the felt packing 5i so that lubricant will not leak out from the housing 49.

On the inner side of the depending annular flange 6I is an annular gear 62 with which meshes a pinion 63 at the upper end of a vertical shaft 64, as shown in Fig. 2. The shaft 64 is mounted to rotate in the bearings 65, 66 and between these hearings the shaft 64 is keyed to a worm gear 61 with which meshes a worm 68 on the shaft49. It will thus be seen that when the motor 44 is operated to rotate the shaft 43 power will be transmitted through the worm gearing 69, 61 and the spur gearing 63, 62 to effect rotation of the'feed plate 51 on the vertical axis of the shaft 54. Such rotation should be in a counterclockwise direction as indicated by the arrow I98 in Fig. 3, so that the inner end of the spiral groove 58 will lead and the outer end will trail, to effectually transfer the pulverized fuel to the annular passageway 69 while atthe same time serving to prevent the pulverized fuel from caking at the bottom of the hopper.

The upper central portion of the feed plate 51 is provided with a hub 69 to which is detachably secured by means of the cap screws 19, 19 an agitator H which has an arm inclined upwardly for travel along a conical path parallel to the inner surface of the'conical hopper 29 and adjacent thereto. The agitator 1I co-operates with the groove 58 in the upper surface of the feed plate 51 to prevent caking'of the pulverized fuel at the bottom of the hopper and to facilitate transfer of the pulverized fuel from all portions of the bottom of the hopper 29 through the port 13 (Fig. 3) to the annular passageway 69.

By-referring to Figs. .1 and 3, it will be seen that the casting II2 of. the housing 32 forms a peripheral flange I I9, the inner surface of which and not more than 39 degrees, for passage of the pulverized fuel from the hopper into the annularpassageway or chamber 69 formed by the casting 2 with said peripheral flange II 9 and by said plate 61 with said flange 59. g

The inner lower edge of the surface 12 overlaps the peripheral edge of the feed plate 51 and is located closely adjacent thereto. Also closely adjacent to the upper surface ofthe feed plate 51 is a pointed annular deflector 14 (Fig. 3) sedeflect pulverized coal from the central portion of theplate 51 toward the port 13 over an area extending from the hub 69 to such opening.

nular passageway 69 while being carried on the annular plate 59, there are provided spacedapart loops of wire'as shown at 16, 16 in Figs. 1 and 3. These wire loops are preferably located so as to travel closely adjacent the bottom I99 of the horizontal flange H9 of the conical casing 12, so that material will not tend to adhere to such lower fiat surface I99.

In order to further assure that the pulverized coal will not form in lumps or become caked, there are provided radial grooves 11, 11 in the upper surface of the annular carrier or conveyor plate 59, it being understood that when the feed plate 51 is rotated by means of the power transmission mechanism including the spur gearing as, 52, the plate 59 together with the radial which is adapted to fit into a slot 84 at the lower end of an arm 85 of a bell crank 86 which is pivoted at 81 to the upper end of the stationary bracket 8|.

Ahorizontal arm 88 of,the bell crank 86 extends through a loop 89 secured to the upper end of a vertical rod 99. Secured to the upper end of the rod 99 is a plate 92 between which and the shelf 93 is a spring 9| encircling the rod 99. This spring urges the plate 92 and the rod 99 upwardly and so also the arm 88 of the bell crank 86. The upper limit of the rod 99 may be adjusted by the nuts 94 which are screw-threaded on the rod 95 secured to the lower end of the rod 99. p

By means of bolts 96, 96 the plate III and the solenoid 91 thereon may be secured to the base frame 36. A plunger 98 extends downwardly into the solenoid 91 and to the'upper end of this plunger is pivoted at 99 a screw-threaded rod I99. A connector I M provided with right hand and left hand screw threads is mounted on the rods 99 and I99 correspondingly. screw-threaded.

By means of the nuts 94 the 'scraper 19 may be adjusted to extend into the annular space 69 a predetermined extent for a running position of the heating system so that a predetermined q-uantity of fuelcould be gradually delivered fromthe hopper to the fan during operation of the motor 44. By referring to-Fig. 4, it will be seen that when the room-thermostat I96 is closed while the main line "switch I93 is closed. a circuit will be established in the supply main terminals I94, I95 through the thermostat switch I96 and the motor 44 and at such time the stack thermostat switch I91 is closed. Therefore, when the room thermostat switch I96 starts the motor 44 it also e fiects energization of the solenoid 91 which is in parallel with the motor 44. The energization of the solenoid 91 pulls down the arm 88 against the action of the spring 9| to move the scraper cured at 15, 15 tothe housing 32 so as to occupy a stationary position and so as to be adapted to 19 to its predetermined maximum delivery position. It can readily be seen, by referring to Fig. 2

I that by means of the connector IN the extent to which the plunger 98 may be moved down may be adjusted and consequently the movement of the scraper 19 in a clockwise direction as viewed in Fig. 3. would be correspondingly adjusted.

That is to say, the running position of the scraper "l8 and the starting position thereof may be independently adjusted because the running position may be adjusted by the nuts 94 and after that has been done the starting position of the scraper 18 may be adjusted by the connector lill. Consequently the running and starting positions of the scraper I! may each be varied accordin to conditions of operation of the heating system.

After the furnace has been operating for a sufiicient length of time to cause the stack switch Illl to open, the solenoid 91 will be de-energized and the spring 9| will move the scraper 19 to its running position where it will remain so long as the room thermostat I I8 remains closed to continue the operation of the motor which drives the feeding and mixing mechanism.

In the operation of the feeder, the bin 29 contains pulverized coal which is maintained in a loose condition by the rotating agitator II which is particularly eifective due to its close proximity to the sloping walls at the bottom of said bin 29. When very loose, the pulverized coal tends to flow much after the fashion of water under the pressure of material in bin 29, particularly when full, and therefore flows through the opening 13 into the annular passageway or chamber 60. Should the pulverized coal tend to cake, the

spiral grooves 58 will cooperate with the agitator 1! to loosen it ,and to convey it laterally to the opening 13, aided by deflector ll.

The material in. the annular chamber ill rotates with the feed plate 51 and flange 59 and the top fingers or loops I8 prevent its adhering to the top of said chamber 60 formed by the surface I09 of flange H0,

The scraper or plow I9 scrapes a redetermined amount of material from the chamber which drops upon chute I02 and slides into inlet opening of the fan casing 48. v

It is to be noted that the opening 13 is of restricted-size. in.that it extends over an arc of feed plate 5'lof considerably less than degrees, and approximately only 30 degrees, andand scraper or plow 19. This insures a uniform feed of material regardless of how full the bin 29 maybe or how free flowing the'material, which is essential to the satisfactory operation of a pulverized fuel feeder, for a non-uniform feed may cause the flre togo out or cause-a feed at such a high rate as to produce an explosion.

Obviously those skilled in the art may make various changes in the details and arrangement of parts without departing fromthe spirit and scope of the invention as defined by the claims hereto appended, and I wish therefore not to be restricted to the precise construction herein disclosed.

Having thus described and shown an embodiment of my invention, what I desire to secure by Letters Patent of the United States is:

1. In feeding apparatus for pulverulent fuel, the combination with a flxed hopper, of a; rotary disc plate forming the bottom of said hopper, an

said hopper, meansadjacent the bottom of said hopper cooperating with said disc and flange to provide an annular chamber into which fuel.

flows through an opening at one restricted position in the bottom of said hopper which extends over an arc of less than 90 degrees, a stationary deflector for guiding fuel from said plate to v said opening, means providing a peripheral fuel discharge opening communicating with said annular chamber which is removed from said first mentioned opening by an arc of at least 90 :degrees; and a deflector for guiding fuel from said annular chamber to said discharge opening.

2. In a feeding apparatus for pulverulent fuel,

' the combination with a hopper having a circumferential flange, of means including a rotary disc plate forming the bottom of said hopper, an annular flange on said disc positioned below the circumferential flange on the hopper, the bottom of said hopper flange cooperating with said disc and said annularflange to provide an annular chamber into which fuel flows through an opening, and projecting arms on the periphery of said disc which travel adjacent the top of'said annular chamber and below the bottom of said hopper flange, said arms being formed of looped wires, said hopper flange extending substantially but not completely around the periphery of the hopper bottom and forming the aforementioned opening.

3. In a feeding apparatus for pulverulent fuel, the combination with a hopper having an interrupted peripheral flange at its bottom, of a. rotary disc plate cooperating with said flange to form the bottom of said hopper, an annular flange on said disc positioned below the peripheral flange. the said peripheral flange cooperating with said disc and annular flange to provide an annular chamber into which fuel flows through a restricted opening formed by said interrupted peripheral flange, and projecting arms on the periphery of said disc which travel adjacent the top of said annular chamber andbelow the bottom surface of said peripheral flange.

'4. In a feeding apparatus for pulverulent fuel,

the combination with a hopper having an interrupted peripheral flange at its bottom, of a rotary disc plate cooperating with said flange to form the bottom of said hopper, an annular flange on said disc positioned below the peripheral flange, the said peripheral flange cooperating withthe said disc and annular flange to provide an annular chamber into which fuel flows of saidhopper, an annular flange on the bottom portion of said disc, means projecting outwardly from the upper portion of said disc, and extending above said flange providing spaced upper and lower surfaces, the lower portion of said hopper being formed with respect to said plate to provide a restricted opening to direct fuel to said flange at one side of said hopper. a plow removed from each extremity of said opening by an arc of at least 90 degrees and extending over said flange .to remove pulverulent material, and means for driving said rotary disc plate.

. 6. In a feeding apparatus for pulverulent fuel, the combination with a hopper/of means including a rotary disc plate forming the bottom of said hopper, an annularifiange on the bottom portion of said disc, means projecting outwardly from the upper portioii'bf said disc and extending above said flange providing spaced upper and lower surfac eaythe lower portion of said hopper being formed with respect to said plate to providea restricted opening to directfuel to said flange at one side of said hopper, a plow removed from one extremity of said opening in the direction of rotation of said disc by an arc of at least 45 degrees and extending over said flange to remove pulverulent material, and means for driving said rotary disc plate.

7. In a feeding apparatus for pulverulent fuel,

the combination witha stationary hopper, of'a rotary disc plate forming the bottom of said hopper, said hopper and disc plate being constructed and arranged to provide a peripheral annular chamber extending over an arc of at least 90 degrees, access to which is provided by a restricted stationary peripheral opening to permit fuel in'said hopper to flow into said chamber at one side of said hopper, and a plow extending into said chamber at a fixed position removed from said opening by an arc of at least 90 degrees to remove fuel therefrom? 8. In a feeding apparatus for pulverulent fuel, the combination with a stationary hopper, of a rotary disc plate forming the bottom of said hopper, said hopper and disc plate being constructed and arranged to form a peripheral chamber having stationary and rotatory walls and extending over an arc of at least 90 degrees, access to which is provided by a restricted stationary opening of not more than 45 degrees arc the comb ation with a stationary casing having an interrupted peripheral flange, of a rotary disc plate positioned adjacent said flange, an annular flange on said disc positioned below said peripheral flange, said peripheral flange cooperating with said disc and annular flange to provide an annular chamber into which fuel is fed through a restricted opening formed by said interrupted peripheral flange, a plow extending into said annular chamber removed from said opening to replate to said port, an agitator carried by said.

plate for rotation therewith at a position adjacent to and substantially parallel with the hopper wall, and means for scraping fuel from said chamber.

11. In feeding apparatus, the combination with a fixed hopper, of means including a rotary disc plate forming the bottom of said hopper, cooperating means carriedby said hopper and disc, respectively, forming an annular chamber at the periphery of said disc plate, said means being constructed and arranged to provide limited access to said chamber from said hopper by forming an opening which extends over an arc of less than 90-degrees, a plow for removing material from said chamber, said plow being located remotely from said opening, said cooperating means forming a substantially completely closed passageway from the extremity of said opening to the point of material discharge by said plow, in the direction of rotationof said disc plate, represented by an arc of not less than 90 degrees.

12. In feeding apparatus, the combination with a hopper, of means including a rotary disc plate forming the bottomof said hopper, means including a stationary interrupted peripheral flange at the bottom of said hopper and an annular flange on said disc plate which cooperate with the periphery of said disc plate to form an annular passageway closed on all sides and extending from an opening to said hopper, formed by said interrupted peripheral flange, to a dis- EARLE v. FRANCIS. 

